Preparation

1. In a small saucepan, stir the jelly over medium heat just until melted. Off heat, whisk in the liqueur. Divide among 4 coupe glasses or 4 small wide bowls and refrigerate until the jelly is firm, about 30 minutes.

2. In a small saucepan, bring 1 cup prosecco just to a simmer over medium heat. In a medium bowl, whisk the sugar and gelatin. Whisk into the hot prosecco. Whisk constantly until the sugar and gelatin completely dissolve, 2 to 3 minutes. Remove from heat. Gently stir in the remaining 1 1/2 cups prosecco (it will fizz up) and pour 1/2 cup into a small bowl. Add 12 blackberries to the bowl and toss until coated. Pour the remaining prosecco over the jelly in the coupe glasses. Add 3 fresh berries to each glass. Refrigerate until set, about 3 hours.

3. Refrigerate the blackberries in the small bowl, tossing often, until the berries are glossy and the gelatin begins to set, about 30 minutes. Transfer the glossy berries to a plate and keep refrigerated.

4. Top each serving with a large dollop of whipped cream and the glossy blackberries.